Swiss ace Roger Federer has admitted world number three Andy Murray is a much-improved player now, adding the Scot would provide a stiffer challenge than ever in the Australian Open semifinal.

Murray and Federer meet for the 20th time on Friday, in the semi-finals of the Australian Open, with the Olympic gold medallist holding a 10-9 advantage, but the world number two has won all three of their Grand Slam clashes, the Daily Mirror reports.

Federer feels Murray is obviously a different player today and has changed his game around a bit, adding that the US Open champion is playing more offensive.

Federer added that Murray proven his point that he can do it time and time again, but it's especially on the return that you see the biggest change in his game overall, if you look back now.

The 17-times Grand Slam winner said Murray is a great player and a great guy, and he was very happy for him when he won his first Grand Slam and the Olympic gold.

Having won his first Grand Slam title in New York last September, Britain's first for 76 years, Murray is bidding to become the first man in the pro era to win the next one. (ANI)